1. Field of Invention
This invention is in the general field of liquid or gaseous material flow regulating systems, and more specifically, concerns a valve that automatically shuts off when flow rates exceed a specified limit.
2. Description of Prior Art
In many applications, it would be desirable to stop the flow of a liquid or gaseous material through various types of conduit if the device that normally controls the flow should become damaged or otherwise inoperable; eliminating the potential for personal injury, property damage, flooding, etc.
Expedience in detecting and automatically shutting off unregulated flow of liquid and/or gaseous material can prevent undesirable, and potentially hazardous, conditions.
There are currently numerous U.S. Patents granted for valves that limit excess or undesirable flow of either liquid or gaseous materials. However, it is believed that this new design offers more flexibility, ease of construction, and desirable operating characteristics than the alternatives currently available.
U.S. Pat. No. 4,174,731 shows an excess flow limiting valve which utilizes a spring to control the movement of a plug assembly.
U.S. Pat. No. 4,825,897 describes a fluid control device in which a weighted spherical ball is positioned in the housing which seats during adnominal fluid conditions in the housing.
U.S. Pat. No. 4,842,198 describes a spring loaded valve which interrupts sprinkler flow when abnormal flow is detected.
U.S. Pat. No. 4,867,603 shows a spring loaded shutoff valve which protects against flooding by broken sprinklers and risers in farming applications.
U.S. Pat. No. 5,613,518 shows a spring loaded valve which restricts excess flow through a conduit.
U.S. Pat. No. 5,857,487 shows a shutoff valve which moves along a guide when excess flow occurs in a sprinkler outlet pipe. The valve described operates with conduits that intersect at rights angles.
U.S. Pat. No. 6,003,550 describes a spring loaded valve which provides positive shutoff and excessive flow shutoff.
U.S. Pat. No. 6,019,115 shows a valve system which controls excess flow that has flow rate settings. The valve is spring operated.
U.S. Pat. No. 5,472,008 teaches a valve for gaseous fluids which protects against dangerous variations in temperatures and flow due to thermal stress.
U.S. Pat. No. 5,465,751 describes an excess flow control valve which has a spring loaded plug that seats upon the detection of unusual pressure.
U.S. Pat. No. 5,462,081 shows a poppet flow valve controller which is spring loaded and includes a poppet element having two sections.
U.S. Pat. No. 5,280,806 teaches an excess flow valve which possesses a magnetically attractable closure element that operates at a particular flow rate of fluid.
U.S. Pat. No. 5,203,365 describes a magnetically operated excess flow check valve in compact form.
U.S. Pat. 4,830,046 shows an excess flow control valve with an internal ball valve biased by a coil spring.
U.S. Pat. No. 4,809,740 illustrates an excess flow limiter in which a slide member is spring loaded and is operated by a button mounted to the outlet chamber.
U.S. Pat. No. 4,574,833 describes an excess flow control device having a reciprocating ferromagnetic armature.
U.S. Pat. No. 4,132,237 shows an excess flow shutoff valve for hazardous fluids which is spring loaded and may also function to stop the action of a pump.
U.S. Pat. No. 4,093,001 shows an excess flow valve for use in a conduit which is provided with a valve disk which may be manually or automatically operated.
The closest known art, U.S. Pat. No. 5,857,487, claims use for only water and the pipes must intersect at right angles. U.S. Pat. No. 4,825,897 claims only use for fluids and states that changes are required for different water pressures.
Valves using a spring device maybe sensitive to aging and pressure variations. Unlike the other prior art valves, the valve of the present application is not affected by variable pressure and has no known aging affects. No other known valve discloses a flow-sensitive piston control closure of the valve.
An object of this invention is to provide an improved excess flow valve which automatically prevents the free flow of liquid or gaseous materials in the event flow rates exceed a specified limit, and which can be used in most conduit systems.
Another objective of this invention is to allow the monitoring of the valve system through ports which can activate remote signaling devices, i.e., red flags, switches, etc., in the event of valve activation.
These and other objects of this invention are achieved by utilizing a flow sensitive piston with a diameter larger than the outlet port""s bore. In the event flow rates exceed a specified limit, sufficient low pressure is generated over the piston""s top surface, drawing the piston against the outlet port""s bore; where its position is maintained by the supply pressure, thus blocking the flow.
The invention consists of certain novel features and details hereinafter fully described, and illustrated in the accompanying drawings, it being understood that various changes in details may be made without departing from the spirit or functions of the present invention.